Hey there! I’ve had that problem before, and it could be an issue with the magnetron or a faulty door switch. I tried fixing it myself, but after a few failed attempts, I called AK Appliance Repair at https://akappliancerepairca.com/ . They provide fast and reliable home appliance repair in Tustin, California. The technician came out the same day, quickly figured out what was wrong, and had my microwave working like new. Sometimes DIY doesn’t cut it, but they were affordable and got the job done quickly. If you’ve tried the basics and it’s still acting up, they’re definitely worth calling!